1. The Field of the Invention
The present invention generally relates to wireless communication networks. More particularly, the present invention relates to balancing traffic load in wireless communication networks to avoid overloading a cell or sector of a cell.
2. The Relevant Technology
Wireless communication networks are today a common means of communication. The demand for wireless services continues to grow, and efficient use of constrained network resources to maximize capacity is of utmost importance to wireless operators. In cellular systems, a geographical area such as a city is divided up into cells. Each cell is served by a base transceiver station, also known as a base station. Often the cell will be further divided into non-overlapping slices called “sectors” to improve capacity. However, in general capacity in cellular systems is still chronically constrained.
As the popularity of wireless telephony and data communication-enabled devices increases, the way in which these devices are used also grows. In addition to the traditional telephone call, one application of wireless technology that continues to gain momentum and popularity is “network-based instant connect communication,” an example of which is Nextel's “Push-to-Talk®” system. Network-based instant connect systems are typically implemented using standard voice-over internet protocol (VoIP) technologies or other data communication technologies, where voice data is sent in digital form over data networks. Unlike standard telephone calls, network-based instant connect communication allows a sender to speak to a recipient without the customary procedure of dialing the telephone number and waiting for the recipient to answer. These services combine the convenience of near-instantaneous connection between users with the range and security afforded by a network, making it a very efficient and secure communication method, especially for large workgroups with inter-dependent workers located on sizable, dispersed corporate campuses, large construction sites, warehouses, and manufacturing floors. Once an instant connect session is established over the network, the voice data transmitted from a sender is played on the recipient's device without any action on the part of the recipient, in a manner similar to traditional walkie-talkie communications. This is in contrast to a regular telephone call where the recipient is required to manually respond to a ringing telephone.
Another example of wireless technology that continues to grow in popularity is the multimedia messaging service (MMS). Generally, MMS is a standards-based, store and forward messaging service that lets users of MMS supported wireless devices send and receive enhanced multimedia messages with formatted text, graphics, photos, audio, and video clips. Similarly, other types of store and forward messaging systems, such as “instant voice messaging systems”, allow a user to transmit voice data to a recipient without having first attempted to place a phone call to the recipient, which could be disruptive or otherwise undesirable.
In addition to the network traffic load already created by standard telephone calls, network-based instant connect communication, store and forward messaging such as MMS messages, instant voice messages and other similar wireless communication methods further impact the demands on wireless networks. For example, the convenience and speed of network-based instant connect communication can drive heavy usage among numerous users, and store and forward messaging systems such as MMS systems and instant voice messaging systems may support one-to-many communication. In other words, a sender of a store and forward message may send such a message to multiple recipients within the wireless network. As such, a single sender can dramatically increase the load on the wireless network proportional to the number of recipients for which the message is intended. Similarly, a single user receiving numerous store and forward messages can also significantly increase load on the network. The traffic load is further exacerbated if senders and receivers or numerous intended recipients are located within the same cell or cell sector.
Although the increased load of sending, for example, a one-to-many store and forward message may not substantially affect the wireless network as a whole, particular cells or sectors within the wireless communication network may be adversely affected. For instance, if multiple recipients of an intended message are within the same cell sector and traffic load in that sector is already substantial, the increased load in the sector resulting from a one-to-many store and forward message may be beyond the available capacity. Such is the case, e.g., in a large warehouse, corporate campus or construction site where a large number of inter-dependent employees or workers are located within a small geographical location and therefore derive wireless connectivity from within the same cell or cell sector. Such inter-dependent workgroups typically use a combination of wireless communication methods, including standard telephone calls, network-based instant connect communication and store and forward messaging systems. Since each base station has limited channel capacity for voice and data communication, the cell and the sectors of that cell are at risk for overload. Accordingly, if heavy traffic has caused most of the available channels of a particular base station to be in use, the transmission of a store and forward message intended for multiple recipients located in a single cell or cell sector may overwhelm the cell in which that base station operates, resulting in failed handoffs, dropped calls, inability to conduct instant connect calls, and unreliable transmission of certain types of messages.